Golang

What does an empty interface in Go look like and what happens if you pass it as a function argument?

How exactly was the process of loading or building this data structured?

What happens to the program if a panic occurs in a separate goroutine?

// code snippet for the best() function // with error handling for no backend available

Imagine that the API you wrote with your team suddenly started responding five times slower. What would you start checking and how would you begin the investigation?

2gis

type Response interface{} type Backend interface { Invoke(ctx context.Context, req Request) (Response, error) } var _ Backend = &BackendImpl{} // addr contains the ip:port of a specific instance func NewBackend(addr string) *BackendImpl type backentry struct { backend Backend inflight int64 } type Balancer struct { backends []*backentry mu *sync.Mutex } var _ Backend = &Balancer{} // addrs contain the addresses of all balancable instances func NewBalancer(addrs []string) *Balancer { data := make([]*backentry,len(addrs)) for i,addr := range addrs{ data[i] = &backentry{ backend: NewBackend(addr), inflight: 0, } } return &Balancer{backends:data} } func(b *Balancer)Invoke(ctx context.Context, req Request) (Response, error){ b.mu.Lock() entry := b.best() atomic.AddInt64(&entry.inflight,1) b.mu.Unlock() defer atomic.AddInt64(&entry.inflight,-1) return entry.backend.Invoke(ctx,req) } func(b *Balancer) best() *backentry{ var best *backentry for _,entry := b.backends{ if best == nil || atomic.LoadInt64(&entry.inflight) < atomic.LoadInt64(&best.inflight){ best = entry } } return best }

What are the types of synchronous and asynchronous inter-service interactions, what tools are used for them, and what have you used in practice?

// code snippet for the best() function // with error handling for no backend available

Why are transactions needed in a database and what problems do they solve?